The occasional use of fibers to reinforce the stopping of the formation of cracks in the technical status is already known, in my U.S. Pat. No. 6,099,638 describes the use of fibers in rheological applications, concrete, micro-concrete and mortar. Although the technical status mentions the use of fibers (for example Garcia Rivero, J. L., “Technical Construction Manual”, published by Cementos Apasco), the mixture of fibers with the components of concrete is prepared in a fresh, i.e., in a damp state. The need to formulate the application in a dry state described in my aforementioned U.S. Pat. No. 6,099,638 led to the development of this invention.
In the particular case of the preparation of concrete and mortars, cement, sand, gravel, additives were used and water was added to start the setting process, and in some cases, reinforcement fibers were added to prior to laying or application. Due to the fluidity of these mixtures during setting, certain means to contain and give them form must be used, for example, the ground, frames, molds or forming.
When the designer decides to use fibers to reinforce the stopping of cracks, which fibers are incorporate in the mix having added water or a precursor agent and dry fibration processes are not used. The incorporation of fibers in the wet mix leads to problems of a lack of uniformity, compactness and stratification of the fibers and the jamming of the mixing equipment. By the other hand, the manner in which the fibers prevent to achieve the mechanical fastening with the rest of the mix. Up to now, these problems have limited the concentration of fibers in the mix and their full use, regardless that by increasing the percentage of the fibers recommended affects and even prevents the correct laying of the concrete in its forming or molds.
Problems arise during the mixing of fibers with wet materials that have prevented the correct incorporation of the fibers because compactness is generated, mixing is difficult or the mix stratifies or settles and a sufficiently uniform mix cannot be obtained. This has limited the range of fiber formulations, reducing it to small proportions in relation to the other ingredients, to the order of 0.02% of fiber by weight in relation to the wet mix or typically 600 g of fiber for each cubic meter of wet mix for formulations based on Portland-type cement with gravel and sand, according to the technical recommendations of the providers of this type of fiber. This proportion is equivalent to 0.024% of the weight of the dry mix (without adding water).
Prior to the aforementioned patent, these fibers were many used to reduce fissures that appeared during contracting while drying in mortars and concrete and with the intention of providing a certain amount of reinforcement for this purpose, although with limited success. Before this invention, there was no process that permitted a successful dry formulation and to date, the manufacturers and the fibration standards themselves recommend or stipulate the application in a fresh state (at the time of mixing) and in a low proportion in relation to the rest of the ingredients.
Said dosing, mixing and wet materials management process used by the technical status is appropriate for applications used in the previous arts on the construction site.
Besides the problems mentioned, there are other additional problems that arise in the application of fiber when using rocky materials, such as (i) the mechanical fastening of the fibers with the rest of the material components (cementants and load) is so low that the mechanical resistance of the fibers is not used to the fall, which prevents it reaching its full capacity in the formulation of the material and (ii) the lack of uniformity in the concentration of fibers in the resulting material.
The process forming the subject matter of this invention solves all of these problems by applying controlled dispersal and abrasion forces that distributes the fibers uniformly, positively modify therefore, maximize the surface area of the solid (fiber)-solid (cementants) interfaces and ensure intimate contact with the cementing components of the mix with the fibers in order to use its resistance to the maximum. The dry mix is homogenous in terms of the concentration of fibers and this homogeneity is maintained when the mix is hydrated or activated for setting and subsequent application. This ensures that the final properties are as intended by the formulation of the mix and increase the possibilities of dosing, multi-fibration and over-fibration of mortar, concrete, micro-concrete and other compound materials. This process increases the capacity of uniform dosing of fibers or micro-fibers and their mechanical fastening, which leads to the commencement of a physical pre-structure process and achieves the positive modification of the properties of the product.
The phenomenon on which this invention is based arises primarily in the dry mix, without spoiling the complementary use of the wet mix method.
This knowledge (which is basic for innovation) has demonstrated that the shortcomings of construction materials is generally due to that constructors do not have access to well-manufactured materials or super-materials (so-called due to their resistance and high-performance).
This novel dry-fibration process is applicable both for concrete and mortar based on Portland or Puzolana cement and for compound materials based on other different types of cementants.